The effects of paclobutrazol on the vegetative growth, reproductive development, total nonstructural carbohydrate of the shoots, and nutrient mobilisation to the leaves of 'Tommy Atkins' mango (Mangifera indica) trees grown in the Rift Valley of Ethiopia were evaluated during the 2002/03 season. The trees used were characterised by excessive vegetative growth, erratic flowering, and fruiting with declining productivity that validated the evaluation of paclobutrazol. Uniform trees were selected for a randomised complete block design experiment with two methods (soil and spraying) and four rates of paclobutrazol (0, 2.75, 5.50, 8.25 g a.i. per tree) in factorial combinations. There were three blocks and three trees per plot for each treatment. The results showed that application of paclobutrazol at rates of 5.50 and 8.25 g a.i. per tree both as a soil drench and spray applications were effective in suppressing vegetative growth compared with the control. Consequently, the trees from these treatments had higher total non-structural carbohydrate in their shoots before flowering. Compared with the control, trees treated with paclobutrazol had higher results for percentages of shoots flowering, number of panicles produced, percentages of hermaphrodite flowers, yield as well as quality of the fruit. Applications of paclobutrazol did not affect the leaf macronutrient content levels analysed (N, P, K, and Ca), and with the exception of manganese, the micronutrient (Cu, Zn, and Fe) levels of the treated tree's leaves were significantly higher than the control.

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The effects of potassium nitrate and paclobutrazol on flowering and vegetative growth of 'Tommy Atkins' and 'Keitt' mango (Mangifera indica) were studied for various periods in inductive and non-inductive temperature regimes. The experiment was done at the University of Pretoria experimental farm in a temperature-regulated cabinet on 2-year-old potted 'Tommy Atkins' and 'Keitt' mango cultivars. 'Keitt' was more sensitive towards low temperature floral induction than 'Tommy Atkins'. For both cultivars, the trend for the interaction of duration and cultivar revealed the possible floral induction complementation effect of PBZ after the trees stayed only 15 days at the inductive temperature (10/15°C). Paclobutrazol also significantly reduced vegetative growth and number of days required for visible inflorescence emergence in both cultivars. Potassium nitrate promoted the initiation of buds for vegetative growth in non-inductive temperature conditions and reproductive growth in inductive conditions. The minimum inductive period at 10/15°C (12 h light/12 h dark) required for "complete" floral induction and development was found to be 35 days for both cultivars. Surpassing the inductive (cold) period showed adverse effects on normal development of the reproductive parts and also delayed inflorescence emergence.

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The effect of different kinds of pruning treatments was studied on Keitt and Tommy Atkins cultivars over two seasons. The trial was conducted at Bavaria Estate, around Hoedspruit area, Northern province of South Africa (latitude: 24o25'S; longitude: 30 54'E; elevation: 600m). With regard to inflorescence development, panicle pruning (during full bloom) at the point of apical bud attachment proved to induce re-flower, more rapid fruit development and more fruit per panicle than the other panicle pruning treatments. Renewal (early in the season when fruit were on the tree) as well as post harvest pruning (especially for early cultivars) treatments were also observed to effect a well-synchronized inflorescence development and adequate number of productive inflorescences per season. Post harvest pruning treatments produced a significantly higher result for the vegetative growth parameters in both cultivars while the control trees showed the lower result. Pertaining to yield, the trend showed that, promising increment could be expected after the second season (with vigilant management of the trees) especially from panicle pruning at apical bud attachment and shoot pruning treatments on 'Tommy Atkins'. 'Keitt' was found to be not responsive to the pruning treatments applied for various parameters observed.